Getting the best value from solar

Size, location and installation are important factors when choosing a solar electricity system. Consider how you use electricity to get the most out of your system.

Size the system to match your electricity use

When considering solar, bigger is not necessarily better. Ideally a system should be sized so most of the electricity it generates is used directly in your home, rather than sold to a retailer. However, larger systems usually cost less per unit of output i.e. a 3kW system may only cost one and a half times as much as a 1.5kW system, rather than double. A solar installation expert will be able to advise on the best system size for a household. They will also consider the amount of roof space available to mount solar panels.

Panels should face the sun and not be shaded

To get the most sunlight, solar panels should face north as much as possible. Panels facing in other direction will work but not produce as much electricity. Ideally there would be no shading of panels from trees, surrounding buildings and hills.

Solar panels are normally fixed at the angle of the roof. Mounting frames can be purchased to adjust the panels to the best angle for the sun. However, in some instances, the cost of these frames may outweigh the added benefit they bring. Consumers should talk to a solar expert about the best option, which could include more panels, or experiment with the solar calculator.

Solar PV panels are suitable for both rural and urban conditions. Panels are usually installed on roofs but you can also place them on facades, conservatory roofs, sun shades, garages or specially built stands on the ground.

 Solar calculator

Use your appliances during the day

Using appliances (e.g. washing machine, dish washer, vacuum cleaner) during the day will increase the amount of solar electricity you use and reduce the amount of electricity that needs to be purchased from a retailer. Showering in the morning rather than in the evening can bring added gains as solar electricity, rather than purchased electricity, is used to heat the water in your cylinder. Consumers with electric vehicles will benefit from charging these during the day, when solar is generating.

Maintain your system

Most solar panels will work for 25-30 years or more, with very little maintenance. For best performance, panels should be cleaned periodically to remove dirt and other debris (e.g. leaves). Very little cleaning might be needed in areas with high rainfall and better air quality but more cleaning may be necessary in areas with poor air quality. Consumers with difficult to access and/or steep roofs may need to pay a contractor to do this work. Trees that shade your panels should be trimmed.

Consumers may need to replace an inverter during the life of their system. An inverter converts the direct current (DC) electricity generated by solar panels into the alternating current (AC) used in New Zealand houses. Inverters come in two main types; string inverters and micro-inverters. Both types have their strengths and weaknesses so consumers should talk to a solar expert about the best option for them.

Get a solar expert to install your system

SEANZ (Sustainable Electricity Association of New Zealand) is the representative body for the solar electricity industry. EECA recommends consumers use SEANZ members to provide advice, quotes and undertake solar installation work.

You need prior approval to connect solar to the electricity grid, so contact your lines company before you start and talk to your electricity retailer also. A solar installation expert will be able to assist with this.

Although you may undertake some of the work to install solar yourself, all electrical work needs to comply with and be certified to NZ electrical standards. Your solar installation must comply with any local council regulations. A building consent is required in some regions, so check with your council before going ahead.

SEANZ website


 Solar electricity systems

 Solar calculator